Production of anhydrous hydrosulfites from aqueous hydrosulfite solutions.



and evaporated almost to dryness in a good UNITED! sTATEs PATENT 'EDUARD MARBURG m) GUSTAV ufinon, on oninsnnrm-on rnn-xein; cinnmnny, ASSIGNOBS 'ro CHEMISOHE'FABRIK GRIESHEIM-ELEKTRON, or nnwxronron- THE-MAIN, GERMANY,'A CORPORATION or GERMANY.

rnonncrron or ANHYnnoUs HYnnosuLFrrEs mom sounous HYDROSULFITE sommrons.

1,207,732. No Drawing.

T 0 all whom it may concern Be it known that we, Emma!) Mannnno and (lus'm'v Minion, both subjects of the (lemma Emperor, and'iesidents ofv (lries- ,l1ci1n on-the-\lain, Germany, have invented certain new and useful Improvemcntsni the Production of Anhydrous Hydrosulfites from Aqueous I-lydrosulfi'te Solutions, of which the follwing'is a specification.

In the specification of U. S. Patent 1,156,107, dated October 12, 1915, a process is described which has for its object the production of anhydrous hydrosulfitcs by the evaporation to dryness of their aqueous solutions in mono and in the presence of anilin or other organic bases. When the process iscarricd out in the manner described in the s ecification of the said patent, the hydrosn is obtained in the form of a fine powder. According to the present invention, which is an improvement upon the process described in. said patent, and in contradistinction thereto, the salt is obtained in a fine-' grained, dense and stable form, by so carrying out the process that the last part of Water can be removed at a.v temperature of about from to- Centigrade. The process is for instance carried out in such a. manner that the hydrosulfitc solution mixed with anilin is evaporatedin a high, vacuum in the usual Way at a. low temperature (say for example, at from 30 to 35 centigrade), until the greater part of the water is removed. Thereupon the remaining part of the ater is distilled off-at from 60 to 65 'ceiitigradein a. suitable vacuum; The

removal of the anilin still present is effected by further distillation in the manner described in the specification of the aforesaid prior patent.-

-The following example will further illustrate how the invention can be carried out,

but the invention is not limited to this oxample: 100 liters ofi sodium hydrosulfite solution are mixed with 50 liters of anilin vacuum while being Well stirred. After the greater part of the waterv has been distilled off, the remainder is driven off at from 60 to 65 centigrade at a pressure of from. 180' ,to millimeters of mercury'and the anilin BpeciflQtion of Letters Patent.

Patented Dec. 12,1916.

. Application filed Inn 9, 191 4. Serial No. 844,028.

is then removed by -further"distillation. -A sodium hydrosulfite ains of from 80 to per cent. content, so tile in theair and of a dense granular constitution. The favorable-action of the anilim is pro ably due to the property, viz. th win and water are soluble-one in the o hei -to limited extent. {Anilin has furthermore the property of forming emulsions, rreadily and thoroughly both with aqueous solutions as well as withwet pulps of a salt. In this way a solid calting of the individualparticles of salt is entirely avoided inf'the' distillation of the water and in addition to this the protecting action of the takes place at all times and in all parts or the mass.

In place of-anilin, similarly acting stabilizing organic bases such/es toluidins may be used.

Having now particularly and" ascertained the nature of out said invention and in what manner the same .is to be per? formed, we declare that what we claim is 1. The process-of removing from partly evaporated hydrosulfite solutions containjingz a suitable organic base, the amount of which base is in excem of that removed by evaporation of the water of the solution; the last parts of xvater and producing anhydrous hydrosulfitesin a stableform, which comprises distilling off the last parts of Water at a temperature of about 60 to 6 5 C. under a suitablg 'vacuum, and removing the or garlic base by further distillation.

2. The process of producing a high per cent. anhydrous hydrosulfiteinstable form comprising subjecting to eveporation'a. mi tture of an aqueous hydrosulfite solution and an organic base, the amount of said basebeing lH GI QCGSS of that'which is removed by the GVZLPOIfEllGlOH of the waten ot the solution. distilling oil the last parts'of water at atemperature of about/601:0'65. C. under a suitable vacuum and removing the base.

comprising subjecting to eva oration amiicent. anhydrous by .osul te instable foi'm such that it is present as a frce'base after the water of the solution is evaporated, dissolution an organic base,

tilling off the last parts of water at a temperature of about 60 to C. under a suitable vacuum and removing the anilin.

4:. The iirocess of producing aul'iydrous hydrosuliites in a stable form, which comprises mixing with an aqueous hydrosulfite the amount of said base beingin excess of that which is re moved by the evaporation of the Water of evaporating said mixture until the greater part of the Water has been removed distilling oil the remainder of the water at a temperature of about 60 to 65 C. under a suitable vacuum, and removing the anilin by further distillation.

. 6. The process of producing anhydrous hydrosulfites in a stable form, which comprises mixing with an aqueous hydrosulfite moved by water has beenieinoved, distilling oil the remainder oi? the water ata temperature of about 00 to 65 C. under a suitable vacuum, and removing the organic base by further distillation.

7. The process of n'oducing anhydrous hydrosulfites in a stable form, which. comprises mixing with. an aqueous hydrosulfite solution anilin the amount of anilin being in excess of that which is removed by the evaporation of the water of the solution, evaporating said mixture while agitating it until the greater part of the water has been removed distilling oil the remainder of the water at a temperature of about 60 to [35 C. under a suitable vacuum, and removing the anilin by further distillation.

ln testimony whereof we have signed our names to this specification in the presence of two subscribing Witnesses.

EDUARD MARBURG GUSTAV MUNCH.

Witnesses JEAN Lianne, CARL GRUND.

of that which is re v the evaporation of the water of the solution, eva 'u'irating said mixtu re while agitating it until the greater part of the 

